Theoretical studies on the electronic structures and optical properties of (Cu, C)-codoped rutile TiO2 from GGA+U calculations.

The electronic structures, formation energy and optical properties of Cu-doped, C-doped, and (Cu, C)-codoped TiO2 were investigated by the projector augmented wave (PAW) method within GGA + U approximation. The results show that the lattice distortion of the Cu@i1&C@i2 system is the largest in all doping systems. The optical absorption edges of the C@i system and the Cu@i1&C@i2 system appear a blue-shift, which is attributed to the band gap expansion and some deep states generation. The Cu@i system exhibits a reduction in band gap and a generation of the hole state, such as it emerges the highest optical absorption in all doping systems.